Removable expansion bolt



Feb. 24, 1931. L. JOHNSTON 1,793,739

REMOVABLE EXPANSION BOLT Filed March 7 1927 gwuemkoi llll 5 n n A a .n n

Gummy Patented Feb. 24, 1931 warren STATES PATENT OFFICE LYNN JOHNSTON, OF CINCINNATI, OHIO, ASSIGNOR TO THE ELECTRIC RAILWAY EQUIP- MENT COMPANY, OF CINCINNATI, OHIO, A CORPORATION OF OHIO REMOVABLE EXPANSION BOLT Application filed. March 7,

Thisinvention relates to expansion bolts such as are adaptable to use for mounting threaded studs in the ceilings of mine passages and the like for receiving trolley hangers.

An object of the invention is to provide a device of this kind which is novel and economical in that it may be removed and used again if desired.

Another object is to provide such removable feature for an expansion bolt structure without necessitating additional expense in extra parts or additional labor.

These and other objects are attained by the means described herein and disclosed in the accompanying drawings, in which:

Fig. 1 is an elevational view of an expansion bolt of the invention, having a hanger mounted thereon, part being broken away.

Fig. 2 is a view taken on line 22 of Fig. 1.

Fig. 3 is a cross sectional view of a section of mine roof having a bolt of the invention mounted therein and having associated there with a tool which may be employed for removing the expansion bolt from its mounting in a ceiling structure.

In the present form of the invention there is employed a sleeve or shell 5, having coarse helical external ridges 6 extending from the top end 7 for a distance along said shell. The shell 5 has a plurality of slots 8 extending longitudinally from the end 7 whereby to provide sections 9 which may be spread apart by means of a tapered conical expander plug 10 which has one or more external ribs 11 which enter slots 8 in the shell to preclude relative rotatory movement of said plug and shell. The plug 10 has a central threaded bore 12 for the reception of a threaded stud 13, which extends through the shell and has its end 14 protruding for a distance from the bottom end 15 of the shell and is ada ted to receive the threaded top portion 1 of a hanger 18; If desired, a nut may be interposed between the bottom 15 of the shell and the top 17 of the hanger.

Upon tightening the threaded portion 17 of the hanger upon the protruding end 14 of the stud, such hanger portion will abut the 1927. Serial No. 173,312.

bottom edge 15 of shell 5 whereupon further rotation will turn the stud 13 which will draw the expander plug 10 downwardly between the sections 9 and spread such sections. If the sleeve'5 has been slidably seated and slightly countersunk into a bore in a mine roof or other ceiling structure, the expansion of the sections 9 will wedge the ridged outer walls thereof tightly into the side wall of such hole and secure the structure in place in a manner well known to those skilled in the art. The simultaneous mounting of the stud 13 and expanding of the shell 5 affords a great saving of time and labor in installing hanger mountings. The bearing flange 16 of hanger 18 is bound in abutment with the surface of the ceiling thereby resisting transverse strains.

Heretofore expansion bolts have been so ditficult to remove without destroying the structure wherein they were mounted that they were invariably allowed to remain in a structure when the location was abandoned. An expansion bolt improperly placed was considered as wasted.

In the present invention the hanger may be removed and theexpansion bolt will remain fixed in the structure if this is desired. In order to permit recovery of the bolt from its firm seat in the structure there are provided two or more notches 19 which extend upwardly from the bottom edge 15 of shell 5.

lVith the hanger 18 removed, a suitable "face spanner tool, for example as shown in 3 may be used. The tool 20 may have a bore or socket 21 of suificient diameter to receive the protruding end 14 of stud 13 and has a suitable number of projecting lugs 22 which may seat snugly in the notches 19 in bottom of sleeve 6.

Rotary movement of the tool'20 will turn the sleeve 5 which will then function somewhat-like a thread cutting tap upon the walls of the bore in which it is secured. Such bores are usually of such depth as to receive the entire shell and the plug 10 loosely entered in the end thereof. The shell may be worked with a tool, such as 20 until it-has cut a comp lete thread in the bore in a mine rootor the like thereby permitting recovery of the entire expansion bolt for re-nse elsewhere.

The formation of the ridges 6 in interrupted helical fashion, renders it easy to use a tool 20 with ample leverage to quickly re claim expansion bolts which would otherwise be lost. Since the sections 9 are spreadat the top of the shell, said shell has the desired taper or clearance for elficiently cutting its way out oit'the mine roof.

It is not intended to limit the invention to the exact structure shown as that may bevaried to accommodate the device to other kindred uses all within the scope of; the appended claims.

hat is claimed is:

1. In a device of the class described the combination with a substance having a bore extending therein, a coarsely and externally threaded and longitudinally slotted ex ansible shell disposed bodily within the ore and having its proximate end spaced from the surface of the substance,- the threads on the expansible shell being of low pitch and shallow depth an expander movable longitudinally in the slottedportion of the shell for expanding said shell and moving the externally threaded portion into binding relation with the wall of the bore in said substance, a bolt receivable in the expander and adapted to be disposed wholly within the bore, and a means comprising a flange :t'or abutment with the surface of the substance and a threaded socket adapted toexten'd into the bore in the substance and to threadedly receive the end of the bolt, said sleeve first moving into end to end abutment with the expans'ible-shell, rotation of said means serving to actuate the bolt for expanding the shell and for rigidly binding said flange against the surface of said substance. the proximate end of the shell being adapted for the reception of a tool when the flanged'means is removed whereby the countersunk shell may be rotated to cause the external threads to-c-ut from the wall of the bore a way to permit removal of the COlll'ltGl'SUllk shell in its expanded position.

2. In a construction of the class described the combination with a substance having a bore ol -indefinite length therein, of a slotted tubular expansible shell for insertion wholly within the bore beyond the outer end thereof, said shell having external interrupted thread-like members of low pitch and shallow depth, an internally threaded expander disposed in the remote endof theshell for expanding the shell to move the exter nally threaded portion into binding relation with the wall of the bore, said expander being wholly free of contact with the; side Wall and. end wall of the bore, a bolt receivable in the threaded bore in the expander and 'a flanged" threaded member a'daptedito be received on the bolt and screwed thereon to e1'1'- gage it's flange-in abutment withtl'iesurface scribed my name this 24th day of the substance, the proximate end of the shell being notched to receive an engaging tool when the flanged means is removed for rotating said shell in expanded condition whereby the external threads may cut a retracting thread into the wall of a substance and permitting removal of the shell.

3. In a construction of the class described the combination witha substance having an unthreaded straight cylindrical bore therein of a longitudinally slotted tubular shell dis posed insa-id bore intermediate its ends and bore whereby topo'sitiontheshell inthebore,

further rotation of the 'han'ger'serving to ex. pand the shell for fixing it into position in the bore, the shell being notched whereby, upon removal of the hanger a. tool may be entered in 'thebore' for rotating the'shell to J effect the cutting :of threads by theexpanded shell for removing the shellfrom the bore in-exp and-ed condition.

In testimony whereof, I have hereuntosubof February,

' LYNN JOHNSTON. 

